(a) Technical Field
The present disclosure relates, in general, to an apparatus and method for the non-destructive measurement of bending stiffness of a gas diffusion layer (GDL) for a fuel cell. More particularly, it relates to an apparatus and method for non-destructively and indirectly measuring the bending stiffness of a GDL for a fuel cell by measuring a sagging length of a GDL sample, which can be used for a fuel cell, without damaging or destroying the GDL sample.
(b) Background Art
In general, a polymer electrolyte membrane fuel cell (PEMFC) is used as a fuel cell for a vehicle. The PEMFC should be able to stably operate over a wide current density range and is typically composed of a fuel cell stack configured by stacking several hundreds of unit cells so that it can exhibit a high-power performance of at least several tens of kW under various operational conditions of the vehicle [S. Park, J. Lee, and B. N. Popov, J. Power Sources, 177, 457 (2008)].
The fuel cell generates electricity through an electrochemical reaction between hydrogen and oxygen in a polymer electrolyte membrane-electrode assembly. Hydrogen supplied to an anode as an oxidation electrode of the fuel cell is dissociated into hydrogen ions and electrons. The hydrogen ions are transmitted to a cathode as a reduction electrode through a polymer electrolyte membrane, and the electrons are transmitted to the cathode through an external circuit. At the cathode, the hydrogen ions and electrons react with oxygen containing air to generate electricity and heat and, at the same time, produce water as a reaction by-product.
When an appropriate amount of water produced during the electrochemical reaction is present in the fuel cell, it performs the function of maintaining the humidity of a membrane electrode assembly (MEA). However, when an excessive amount of water is present and is not appropriately removed, a flooding phenomenon occurs at high current density, and the flooding water prevents the reactant gases from being efficiently supplied to the fuel cell, which results in an increase in voltage loss.
Therefore, in order to improve the productivity of the fuel cells stacks for fuel cell vehicles and stabilize their quality, it is necessary to efficiently assemble and test the parts of the fuel cell stacks and, at the same time, to rapidly and accurately measure the properties of the parts of the fuel cell stacks.
There remains a need in the art for apparatus and method for non-destructive measurement of bending stiffness of a gas diffusion layer (GDL) for a fuel cell, that can be used without damaging or destroying the GDL sample.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.